The invention relates to a device for rotating a body about two axes.
By means of this device it is possible to introduce tilt movements (rotation about a horizontal axis) and swiveling movements (rotation about a vertical axis) into a body, for example an optical device. Such rotating movements are often required for the effective operation of remote-controlled cameras, but also of other devices, for example from the field of optics, such as light sources (searchlights, lasers, etc.).
Moreover, devices for rotating a body about two axes are also employed for moving tools in connection with robot technology.
Often the bodies to be rotated must be in electrical contact with an electric unit, for example for the exchange of signals or for transmitting an electrical current supply. Usually this electrical unit does not participate in the rotating movements of the body to be rotated and is arranged fixed in place. Collector rings are employed for making an unrestricted rotating movement of corresponding bodies about 360xc2x0 possible.
A device for tilting and swiveling a camera is shown in U.S. Pat. No. 4,673,268. The collector ring described there is used both for transmitting the drive currents for the displacement motors, which rotate along, as well as for signal transmission. For this purpose, the collector ring was installed fixed in place and axially not displaceable in the support of the device.
Publication EP 0 714 579 B1 also discloses a device for tilting and swiveling a camera, wherein the drive mechanism responsible for the swiveling movement is fixed in place on a base plate. But the drive mechanism causing the tilting movement is arranged in such a way that it rotates when a tilting movement is performed. The collector ring provided for operating the device is also fastened stationary and axially not displaceable on the base plate.
A device for rotating a camera about two axes is also shown in DE 297 12 356 U1, wherein a swiveling motor is located on a rotatable component. In the arrangement shown there, the collector ring is not movable in the axial direction. Moreover, it can also not be stressed axially, because the two collector ring components of rotor and stator are mechanically separated when axial forces are applied.
The known devices have the disadvantage that at least one electrical rotary drive mechanism rotates along with the body to be rotated. This drive mechanism must be supplied with electrical energy via the collector ring, which makes the construction of the collector ring more elaborate. Added to this is that an electrical rotary drive mechanism has a not inconsiderable inert mass, which in turn causes considerable reaction forces, or moments, in connection with large angular accelerations. Often the dynamics of the entire device for rotating a body, inclusive of its drive mechanism, are limited by the mass moment of inertia, and therefore also by the mass of the components to be moved or, for a preset angular acceleration, requires the dimensioning of the relevant components to a corresponding extent.
The invention is therefore based on the object of providing a device for rotating a body about two axes, which is distinguished by simple construction and comparatively small inert masses.
This object is attained by means of a device in accordance with claim 1.
Advantageous embodiments of the device of the invention ensue from the steps in the claims depending from claim 1.
The advantage obtained by means of the invention rests in that by means of the novel device, the drive mechanisms for rotation about the two axes can be arranged fixed in place. In this way the entire structure is simplified inter alia, in that the collector ring has fewer sliding contacts. If desired, the collector ring can be embodied without contacts for transmitting a drive current, so that only sliding contacts for electrical low voltage signals must be provided. On the other hand, by avoiding drive mechanism which rotate along, it is possible to reduce the mass to be moved and therefore the mass moment of inertia of the entire device, so that the movement dynamics of the body can be increased. Moreover, by means of the invention a simpler and material-saving structure of the device for rotating a body about two axes is possible because of the reduced mechanical stresses.
The invention is particularly based on the concept that rotating movements are introduced into the body to be rotated by means of axial movements of the collector ring. The expression xe2x80x9caxial directionxe2x80x9d always is meant to be the direction of the collector ring axis.